Stories from the Institution of Engineering and Technology

Amongst our S P Thompson collection of pamphlets there is a volume of pamphlets titled ‘Burning Mirror of Archimedes’, which amongst other things contains several early pamphlets on the subject. One such example is the 1732 pamphlet illustrated above, written by Johann Andreas Segner (1704-1777), the Hungarian scientist. More of this later, but what is a burning mirror and what has this got to do with Archimedes!

A burning glass or burning lens is a large convex lens that can concentrate the sun’s rays onto a small area, heating up the area and thus resulting in ignition of the exposed surface. Burning mirrors achieve a similar effect by using reflecting surfaces to focus the light and were used in 18th century chemical studies for burning materials in closed glass vessels.

However, the history of burning glass and burning mirrors dates back to antiquity, and there is a legend associated with Archimedes, the renowned mathematician, which says that he used a burning mirror as a weapon in 212 BC when Syracuse was besieged by Marcus Claudius Marcellus. The Roman fleet was supposedly incinerated, though eventually the city was taken and Archimedes was slain.

Whether there was any truth in this legend, and whether it is indeed possible to destroy ships using giant mirrors, has fascinated scientists for centuries, and even featured in a US TV show, Mythbusters, where the US President Barack Obama, challenged the hosts to test the problem and come to a definitive conclusion. This history of this legend and scientists’ attempts to prove it or disprove it can be found on the ‘UnMuseum’ website – Archimedes and the Burning Mirror

Within the volume of pamphlets is a manuscript paper written by S P Thompson, Professor of Physics, in which, after analysing the physics and mathematics of ‘the legend’, he concludes that the story cannot be true!

Johann Andreas Segner

The author of the pamphlet shown above, Johann Segner, was born in the Kingdom of Hungary in the former Hungarian capital city of Pozsony (today known as Bratislava but also known in the 18th and 19th centuries by its German name of Pressburg). He initially studied in Pressburg but then in 1725 went to the University of Jena (one of the oldest universities in Germany) where he received a medical certificate in 1729 before returning to Pressburg where he began work as a physician. Johann returned to Jena for his master’s degree in 1732 (the earlier pamphlet was published in Jena which is printed in Latin as ‘Ienae’).

In 1735 Segner became the first professor of mathematics at the University of Göttingen and in 1755 became a Professor at Halle where he established an observatory. He is known as the father of the water turbine after constructing the first water-jet, the Segner wheel.

Raphael Mirami’s 16th Century pamphlet ‘Compendiosa Introduttione….’

An even early pamphlet in this SP Thompson volume, printed in 1582, is Raphael Mirami’s 2-part publication shown below.

This is Mirami’s only known publication which combined a scientific interest in mirrors and optics with poetry including verses from Dante, Petrarch and Horace and even his own sonnet! Mirami identified himself as a Jewish physician and mathematician from Ferrara, but there are suggestions that this is a pseudonym.

Woodblock Printing

For those people interested in typography, the Segner and Mirami pamphlets contain many beautiful woodblock print letters and illustrations including those shown below. Given our extensive collection of rare books with many dating from the 16th and 17th centuries we are now investigating the merits of setting up a new IET Archives Pinterest board dedicated solely to woodblock letters!

Letters and Book Collecting!

Although the ‘burning mirror’ volume contains predominantly pamphlets, there are also some fascinating letters and an insight into S P Thompson’s book collecting habits!

There are two letters discussing burning mirrors and lenses from Robert Miller Christy, known as Miller Christy (1861-1928), a member of a well-known Quaker family who was a respected authority and author on archaeology and ornithology in the English county of Essex. In one of the letters, from 1906, Miller refers Thompson to Dr E K Kane, “who when on the Grinnell Artic Expeditions (about 1845) made and successfully used an ice lens”. Dr Elisha Kent Kane (1820-1857) was an American explorer and US Navy medical officer who took part in two Artic expeditions to search for the lost explorer Sir John Franklin.

How did S P Thompson know Miller Christy? Well, perhaps there is a clue in one of Miller Christy’s letters, when he says, “I wish to thank you for the very pleasant evening I spent with The Odd Volumes on Tuesday evening through your kind invitation”.

The ‘Sette of Odd Volumes’ was an English bibliophile dining club founded in 1878 that was formed to help members research and collect first and rare editions of books, and Silvanus P Thompson was a member of the Odd Volumes. The members were each given a ‘special’ title and Thompson’s title was ‘the Magnetiser’. A letter sent to Thompson in 1910 by Arnold Clarke on Odd Volume stationery is shown below. The letter talks about producing a year-book, covering Odd Volume events that took place in 1906/7, that would include an abstract of Thompson’s paper on the Burning Mirror of Archimedes that Thompson presented to the group on 27 November 1906.

For anyone wishes to consult the conserved volumes from the collection of S P Thompson pamphlets, they can be viewed at the IET Archives, by appointment.